|Publication number||US20060152426 A1|
|Application number||US 11/032,914|
|Publication date||Jul 13, 2006|
|Filing date||Jan 11, 2005|
|Priority date||Jan 11, 2005|
|Also published as||EP1679764A1, US7138952|
|Publication number||032914, 11032914, US 2006/0152426 A1, US 2006/152426 A1, US 20060152426 A1, US 20060152426A1, US 2006152426 A1, US 2006152426A1, US-A1-20060152426, US-A1-2006152426, US2006/0152426A1, US2006/152426A1, US20060152426 A1, US20060152426A1, US2006152426 A1, US2006152426A1|
|Inventors||Daniel McGrath, Timothy Shively|
|Original Assignee||Mcgrath Daniel T, Shively Timothy H|
|Export Citation||BiBTeX, EndNote, RefMan|
|Referenced by (1), Classifications (12), Legal Events (3)|
|External Links: USPTO, USPTO Assignment, Espacenet|
The present invention relates generally to the field of array antennas and more particularly, but not by way of limitation, to an array antenna with dual polarization and method.
Electronic scanning antennas capable of dual polarization are beneficial in a variety of applications. For example, the utilization of such antennas in a synthetic aperture radar allows the production of clearer imagery due to the scattering properties of various objects. In yet other applications, dual polarization can be utilized to facilitate rejection of cross-polarized interference and to facilitate the rejection of rain clutter. A variety of other applications, utilizing dual polarization antennas, are readily recognized by those skilled in the art.
According to one embodiment of the invention, an array antenna includes a substrate body, a first antenna element, and a second antenna element. The first antenna element is coupled to the substrate body and is operable to transmit or receive a first signal. The second antenna element is coupled to the substrate body and is operable to transmit or receive a second signal. The first antenna element is of a different type than the second antenna element. The direction of polarization of the first signal is different than the direction of polarization of the second signal.
According to another embodiment of the invention, a method of transmitting or receiving signals with two different polarizations from an array antenna includes providing a first antenna element and providing a second antenna element. The first antenna element is different than the second antenna element. The method also includes transmitting or receiving a first signal having a first polarization from the first antenna element and transmitting or receiving a second signal having a second polarization from the second antenna element. The direction of the second polarization is different than the direction of the first polarization.
Some embodiments of the invention provide numerous technical advantages. A technical advantage of one embodiment of the present invention may include the capability to provide dual polarization array antennas with decreased complexity and/or cost. Other technical advantages of the present invention may include the capability to utilize a common substrate for feed lines that drive antenna elements with different polarizations.
While specific advantages have been enumerated above, various embodiments may include all, some, or none of the enumerated advantages. Additionally, other technical advantages may become readily apparent to one of ordinary skill in the art after review of the following figures and description.
For a more complete understanding of embodiments of the present invention and their advantages, reference is now made to the following description, taken in conjunction with the accompanying drawings, in which:
It should be understood at the outset that although example implementations of embodiments of the invention are illustrated below, the present invention may be implemented using any number of techniques, whether currently known or in existence. The present invention should in no way be limited to the example implementations, drawings, and techniques illustrated below. Additionally, the drawings are not necessarily drawn to scale.
While dual polarized array antennas have numerous advantages, the production of some dual-polarized array antennas can be either labor intensive or cost-prohibitive. For example, some configurations (namely, cross-notch configuration or cross-dipole configurations) create a dual-polarization effect by positioning similar radiating elements at right angles to one another. In these configurations, the radio frequency feed lines (utilized to couple signal sources to the radiating elements) can not remain coplanar. Rather, at least one of the feed lines needs a bend, twist, or some other transition to connect to its respective element. Such bends and/or twists undesirably increase the time and/or expenses involved in creating the dual-polarized array antenna. They also cause reflections and loss that reduce the antenna's efficiency. Accordingly, the teachings of the invention recognize that it would be desirable for a configuration that could create such a dual-polarization array antenna, yet avoid and/or minimize the above concerns. Embodiments below address such concerns.
In this embodiment, two types of antenna elements 10 are utilized: monopole radiators 60 and flared notch radiators 70. Each monopole radiator 60 is paired with a flared notch radiator 70. In such a pairing, the monopole radiators 60 are shown centered between the flared notch radiators 70 to form an interleaving of the antenna elements 10. Although such a configuration is shown in this embodiment, it should be understood that other configurations can be utilized in other embodiments of the invention. In such other embodiments, other types of antenna elements 10 can be utilized. For example, antennas elements 10 other than flared notch radiators 70 and monopole radiators 60 can be utilized.
The operation of flared notch radiators 70 and monopole radiators 60 should become apparent to one of ordinary skill in the art. In this embodiment, the monopole radiators 60 are vertically polarized while the flared notch radiators 70 are horizontally polarized. Thus, the direction of the polarization of the monopole radiators 60 is orthogonal to the direction of the polarization of the flared notch radiators 70. With the description of polarization of the antenna elements 10, it will be recognized by one of ordinary skill in the art that such polarized antenna elements 10 (the monopole radiators 60 and the flared notch radiators 70) can be utilized to transmit and/or receive a signal. For example, in some embodiments, both sets of antenna elements 10 can transmit and receive signals. In other embodiments, both sets of antenna elements 10 can transmit signals, while only one antenna element 10 receives signals. In yet other embodiments, both antenna elements 10 can only receive signals or both antenna elements 10 can only transmit signals. Yet further configurations can be utilized in other embodiments as will be recognized by one of ordinary skill in the art. In some embodiments, each pair of orthogonal elements may be driven by a device that controls their relative amplitude and phase in order to produce a radiated field with a specific polarization.
While specific configurations of the monopole radiators 60 and flared notch radiators 70 have been shown, a variety of other configurations can be utilized in other embodiments. For example, the flared notch radiators 70, while shown having an exponentially tapered notch in
The monopole radiator 60, shown removed from the substrate 80, can be affixed to the upper layer 80A to hold the monopole radiator 60 in position and facilitate the electric conductivity, described below. A variety of techniques can be used for such affixing, including, but not limited to soldering, affixing with conductive epoxy, welding, ultrasonic boding, and the like. To facilitate this affixing, the monopole radiators 60 are preferably made of metallic materials such as copper, brass, gold, silver, or the like.
The lower layer 80B of the substrate 80 includes a horizontal polarity feed line 82 and a vertical polarity feed line 86. Each horizontal polarity feed line 82 (only one explicitly shown in
With reference to
The spacers 50 in
One of ordinary skill in the art will recognize that embodiments of the invention are capable of providing effective wide angle scanning in an array environment. Some embodiments can additionally produce desirable levels of isolation and orthogonality when measured over varying scan angles. As an example of these measured levels, isolation can generally be the measure of power coupled to the flared notch radiator when the monopole radiator is transmitting or vice versa. Orthogonality can generally be a measure of the difference in polarization states radiated by each of the elements in the interleaved array pair.
Although the present invention has been described with several embodiments, a myriad of changes, variations, alterations, transformations, and modifications may be suggested to one skilled in the art, and it is intended that the present invention encompass such changes, variations, alterations, transformation, and modifications as they fall within the scope of the appended claims.
|Citing Patent||Filing date||Publication date||Applicant||Title|
|US7683847 *||Nov 14, 2006||Mar 23, 2010||Selex Sensors And Airborne Systems Limited||Antennas|
|Cooperative Classification||H01Q1/38, H01Q9/30, H01Q13/085, H01Q21/28, H01Q21/24|
|European Classification||H01Q13/08B, H01Q9/30, H01Q21/24, H01Q1/38, H01Q21/28|
|Jan 11, 2005||AS||Assignment|
Owner name: RAYTHEON COMPANY, MASSACHUSETTS
Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNORS:MCGRATH, DANIEL T.;SHIVELY, TIMOTHY H.;REEL/FRAME:016176/0165
Effective date: 20050107
|May 3, 2010||FPAY||Fee payment|
Year of fee payment: 4
|Apr 23, 2014||FPAY||Fee payment|
Year of fee payment: 8